Snow melting devices known in the art commonly utilize a burner unit or assembly to provide heat to a snow melting medium, typically water. The heated medium is then used in various ways to melt the snow.
Canadian Patent No. 780,673 and U.S. Pat. No. 3,187,743 (both to Primas) disclose a snow melting device commonly known in the art. This device includes a tank and a fuel burner assembly. The burner assembly includes a downwardly extending downcomer tube which encloses the fuel burner nozzle. The downcomer tube is provided with an opening at the bottom for the outflow of combustion gases from the sides, and a closure plate disposed over the end thereof at a slight distance therefrom. A tubular housing, or weir, is provided around the downcomer tubs with a bottom opening, and with an upper opening at a location above the lower end of the downcomer tube for the outflow of combustion gases and hot water. The burner assembly is positioned inside the tank, into which snow is introduced for melting. In operation, water is supplied to a specified height in the tank, the burner is ignited, and combustion gases are discharged downwardly from the burner nozzle through the downcomer tube and out through the bottom openings beneath the water surface. The combustion gases, on exiting the “slots” (20), break down into millions of minute bubbles as they contact the water present in the annular space. The instantaneous mixing and transfer of heat to the water causes an immediate decrease in bulk density of the mixture causing the mixture to rise vertically up the annular space inside the weir and violent discharge thereof out of the opening at the top of the weir. A deflector plate positioned at the top opening directs the heated water laterally onto the snow in the tank. The heated water strikes the upper surface of the snow in the tank and melts it. The tank disclosed by Primas is designed to maintain a body of water as a melting source and for cooling of the burner assembly.
U.S. Pat. No. 6,736,129 (Smith) discloses another example of a snow melting apparatus in which a container, or tank is provided with a burner having a modified combustion chamber. At least a portion of the combustion chamber is submerged in the snow melting medium, i.e. water. The submerged portion of the combustion chamber includes a horizontally extending sparger tube through which combustion gases emerge. The combustion gases cause nucleate boiling and strong agitation from below the water level and thereby accelerate the melting process. The disclosed snow melting apparatus also includes a mechanism for removing debris from the snow, and a control mechanism to maintain an optimal water temperature for maximum fuel efficiency. A pumped recirculating water system is also described for cooling the portion of the combustion chamber not submerged in the snow melting medium.
A variety of other examples of snow melters are also know in the art. For instance, U.S. Pat. No, 6,305,105 (Lowman) discloses a device for disposing of snow deposited on a surface e.g., roadways, sidewalks, etc. The apparatus includes a mechanism that removes snow from the surface and guides it into a snow melting apparatus comprising three chambers. Within the first chamber, heated, pressurized water is sprayed onto the snow to aid in the melting process. The second chamber has an agitating device that moves and separates the snow/water mixture into a slurry to melt it. The third chamber, or tank, is connected to the second chamber and stores the melted snow. The system further includes a screen to prevent stones or other debris from entering the heat chamber.
In U.S. Pat. No. 5,235,762 (Brady), a snow melting apparatus is described having a reduction chamber into which heated air is forced by a burner. Heated water is also distributed within the reduction chamber by using a pump and perforated pipes. The burner is controlled by a thermostat to keep the temperature of the water consistent. The water used for the snow melting process is stored in a separate reservoir.
U.S. Pat. No. 5,791,335 (Luciani) discloses a snow melting apparatus comprising a hopper which forms a lower trough, a pivoting ram/screen assembly to prevent large debris from passing to the trough, and a manifold having a plurality of rotating sprinkler heads for discharging heated water onto the snow and debris introduced into the hopper.
United States Patent Application Publication No. 2004/0074114 and Canadian Patent Application No. 2,450796 (both to Rogers) describe a snow removal system comprising a container having a storage chamber adapted to store snow and a predetermined amount of water, and a heating assembly which is at least partially disposed in the storage chamber. The heating assembly is adapted to heat water stored in the storage chamber to a selected temperature. The system also includes a mixing system adapted to pressurize water and discharge the pressurized water onto the snow. Debris can be evacuated using a door disposed on a wall of the storage chamber.
Canadian Patent No. 769,461 (Petlak) describes a snow melting machine having manifold ducts and pipes placed in parallel to evenly distribute hot gases in a melting chamber. Hot gases are expelled in a downward direction below the water level in the tank toward the bottom of the chamber. The apparatus thus requires the tank to be filled with water prior to initiating the melting process.
Canadian Patent No. 907,989 (Coslowsky) discloses an automatic snow melter comprising a melting chamber mounted on a truck, a rotary agitator for agitating the snow and means for separating debris and rocks. In the melting chamber, the snow is passed under gas jets which quickly melt the snow to fill the chamber with water.
Canadian Patent No. 741,959 (Gontcharuk) discloses a snow disposal apparatus comprising a rotatable heating chamber for continuously mixing snow and water, and burners that allow for hot air to be blown into a tube which is horizontally fixed under the snow.
Canadian Patent No. 712,840 (Glaser et al) describes a snow melting apparatus which uses hot combustion gases to preheat water in a melting chamber. When the water of the melting chamber reaches a certain temperature, snow or ice is added to the chamber for melting.
A common problem of such prior art devices is that water must be supplied in sufficient quantity to provide cooling of the burner assembly prior to ignition of the burner. This results in a need for water to be readily available at the site of operation, restricting the use of such equipment to sites having a water source in close proximity. Otherwise, water must be transported from site to site in a reservoir associated with the snow melter.